This invention relates to an ultraviolet-curing silicon-containing resin composition that can be used to fabricate dielectric films in semiconductor devices, and to a method for forming cured silicone patterns using said composition.
Silicone resins are widely used as electrical and electronic materials due to their generally high heat resistance and excellent electrical characteristics. Among these, curable silicone resins are used to coat substrate surfaces. The heat-curing types in general cure through the hydrosilylation reaction, silanol condensation reaction, or siloxane bond-forming reactions based on alcohol, oxime, or acetic acid elimination. UV-curable silicone resins become important when considering factors such as the heat tolerance of the substrate, cure rate, or selective curability.
Cured regions in which crosslinking has been induced by the above-described methods as a general rule have a substantially lower solvent solubility than the uncured regions, and the exploitation of this feature makes imaging possible.
Vinyl- and mercapto-functional silicone can be cured by UV in the presence of oxygen. The technology using the addition of mercaptan to olefin suffers from the odor and corrosivity due to the mercaptan. Air (oxygen) induces cure inhibition where the curing technologies employ the radical polymerization of functional groups as acryloyl, methacryloyl, and so forth. Moreover, the resulting crosslinking moiety has a low thermal stability, and thus the cured products are not robust to use and processing at high temperatures.
The epoxy-functional silicones and vinyl ether-functional silicones are generally cured using a substance that generates acid upon photoexposure. This acid facilitates substrate corrosion while the electrical properties of the cured products are impaired by the ionic impurity.
Silanol-functional silicones and Si-H-functional silicones can be cured through the use of a substance that generates base upon photoexposure, and the resulting cured products thus contain a base. This base also causes various problems, such as impairing the electrical properties of the cured product and causing long-term changes in mechanical properties due to siloxane bond rearrangement. The silanol-functional silicones can also be cured using a substance that generates acid upon photoexposure (Japanese Patent Application Laid Open [Kokai or Unexamined] Number Hei 6-80879 [80,879/1994]). This technology, however, suffers from the same problems as described above for the epoxy-functional silicones and vinyl ether-functional silicones.
Thus, as described above various cure technologies are known for photocurable silicones, but in each case one encounters problems.
It is therefore an object of this invention to provide a storage-stable UV-curable composition whose cure is not inhibited by air or oxygen, which is very efficiently cured by low doses of UV radiation, and which provides a highly heat-resistant cured pattern through the execution of a post-patterning heat treatment.
It is further an object of this invention to provide a method for the formation of cured patterns using the UV-curable composition.